Writing of a hard up worker (9)
I believe the answer is:
shorthand
'writing' is the definition.
(I know that Shorthand is a type of writing)
'hard up worker' is the wordplay.
'hard up' becomes 'short' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'worker' becomes 'hand' (hand is a kind of worker).
'short'+'hand'='SHORTHAND'
'of a' acts as a link.
Can you help me to learn more?
(Other definitions for shorthand that I've seen before include "Method of abbreviated writing" , "Rapid writing language" , "aid to office work?" , "Pitman's invention" , "Aid to taking dictation" .)